Increasing the interval (lag) between presentations of repeated items produces large concommittant increases in the recall of the items. Five preliminary experiments are proposed to extend our empirical and theoretical knowledge of repetition effects, and this lag effect in particular. The first experiment, using a nominal free recall paradigm, assesses the strength of the lag effect in relation to cued recall and free recall and the mnemonic instructions given to the subjects. The second experiment traces the course of the effect in a continuous recognition memory task. Experiment three provides for the measurement of the lag effect after a 24-hour retention interval, and the extension of the lag effect to presentations between (free recall) lists. Experiment four tests the joint effects of the interpresentation lag and variations of the situational contexts during the input and retrieval stages of free recall lists. The fifth experiment explores the implications of past research on the lag effect on memory for connected discourse. This experiment begins the development of an entirely new research area that can be refined and extended in many directions. All five experiments have a direct bearing on a theory of lag effects proposed by Glenberg (1974). The theory juxtaposes a theory of variable coding at input, with a theory of cueing and retrieval at output. The five experiments are intended to refine and extend this theory into a general theory of repetition effects in human memory.